Grinding ball



Patented Sept.l 15, 1931 UNITED STATES PATENT OFFICE WIABBEN F. CLEMENTS, OF ALLENTOWN, PENNSYLVANIA, ASSIGNOR T FULLER LEHIGH COMPANY. OF FULLER'ION, PENNSYLVANIA, A CORPORATION 0F DEL- AWARE GRINDING BALL Application led March 6, 1929. Serial No. 344,700.

This invention relates to grinding balls and the process of making them for use 1n mills for grinding material such as coal, for example, in which balls are pushed 4around over a grinding surface.

The invention will be understood from the description in connection with -the accompanying drawings in 'which Fig. lis a side view of half of a mold in which the balls are cast, showing a ballin section; and Fig. 2 is a section along the line 2 2 of Fig. 1.

In the drawings reference character 1 indiates half or one side of a mold that may be made of cast iron that is made in two halves that can be clamped or bolted together. Each half of the mold is provided on its inner face with a hemispherical opening 2 into the lower side of which a groove/or passageway 3 for molten material leads from the upper side 4 of the mold. A riser 5 extends from the upper edge of the spherical opening 2 along the inner face of each half of the mold to the upper surface of the mold. When the halves of the mold are put together they enclose the spherical opening into which metal for forming the ball can be introduced through the inlet or groove 3.

Recesses 6 are provlded inthe inner faces of each half of the mold around the edges.

of the hemispherical openings, 'so that a previously cast spider 7 with arms 8, having the ends thereof extending into said recesses 6, can be put in place before the halves of the mold are put together. The spider 7 may also be provided with shorter arms 9, extending arms 8. v

In producing the balls, the spider 7, which is preferably made of grey iron, is put' in place with the ends of its arms 8 extending into the recesses 6, the-two sides of the mold assembled and molten iron is poured through the inlet 3 filling the spaces in the spherical opening around the spidei` 7 and arms 8 and 9. This molten iron may be of silica iron that w1l1 become chilled to a certain extent in the mold as it solidiies and knits around the spider 7 and aljms 8 and 9. .The mold'is then opened and the protruding ends of the arms removed to leave a smooth spherical surace.

It has been found that when a metal castingl or spider is used as described above around whichl the ball is poured, no large mass remains hot at the centerafter the surface is coolednvith the result that there are less internal strains in the ball as a Whole When it is finished.v which makes it less liable to break when used as a grinding ball.

I claim:

l. A grinding ball having an inside spider of soft iron and the remainder of hard iron, said spider having arms extending into said fhard iron.

2. A grinding ball having an inside spider of grey iron and the remainder of silica iron, said spider having arms extending into said silica iron.

3. A grinding ball having an inside spider of soft iron and the remainder of hard iron, said spider'having arms, the ends of which terminate at the surface of said ball.

4. A grinding ball having an inside spider of soft iron and the remainder of hard iron, said spider having radial arms some of which terminate at the surface of said ball.

WARREN F. (ELEMENTS.

at right angles to the plane of the y 

